I have been on all sorts of tetracyclines on & off for 5-6 years now & have not experienced this effect. I do find that yeast grows more easily in the mouth though (the white pasty stuff in the morning- sorry for the gross factor) so good dental hygiene is a must.

I've experienced no real side effects of tetracyclines apart from a doxy getting stuck in my oesophagus once- but it was my fault for taking it 2 minutes before lying down to bed. Caused heartburn the next day but nothing too bad.